In a disk brake device, to obtain high braking force, it is desired to employ a large-diameter rotor, whereas a disk brake device to be stored in the inside diameter of a wheel is restricted in space when mounting it.
From this viewpoint, a caliper body constituting a disk brake device is strongly demanded for miniaturization. Further, to enhance the motion performance of a vehicle, the device is also required of weight reduction. Here, when compared with an opposed type disk brake device having pistons on both inner and outer sides of a rotor, a floating type disk brake device is proper for miniaturization, weight reduction and inexpensive production.
In the floating type disk brake device, as a device proposed especially for miniaturization and weight reduction, there is known a device of a type disclosed in the patent document 1 and 2. The disk brake device of the patent document 1 and 2, normally, employs a structure in which a pressure plate serving as the back plate of a brake pad disposed on the outer side of a rotor is used, instead of a pawl part disposed on the inner side of the rotor, as a reaction force receiver for receiving a pressing force given by a piston. That is, the pressure plate of the outer side brake pad, as it is, is fixed as a part of a caliper body.
The thus structured disk brake device can surely realize miniaturization and weight reduction. However, since the reaction force receiver is constituted of only the pressure plate, there is a fear of the caliper body being insufficient in strength.
Also, the patent document 3 discloses a floating type disk brake device which eliminates the outer bridge of a support conventionally disposed on the outer side of a rotor to thereby reduce the weight of the whole device. In the disk brake device of the patent document 3, the pressure plate of an outer side brake pad conventionally guided by the support on the outer side is bolt fixed to a pawl part serving as the reaction force receiver of a caliper body. In the thus structured disk brake device, the pressure plate reinforces the rigidity of the caliper body, whereas the bridge of the caliper body is small in thickness. This raises a fear that, in braking, an amount of tilting in the caliper body can increase to thereby cause uneven wearing or the like.
Further, the patent document 4 discloses a disk brake device which includes a frame for surrounding the lower side edge portion of a caliper in order to enhance the stability and twist rigidity of the caliper. In the thus structured disk brake device, the outer side bridge of a support for connecting together the rotor turn-in and turn-out sides of the outer side frame of the support is eliminated for weight reduction. An outer side brake pad is spring supported on a pawl part to enable the pawl part of the caliper to receive brake torque in part, whereby the rigidity of the whole caliper is enhanced by a frame surrounding the edge portion of the caliper.
As a technique for enhancing the performance of a disk brake device, there is known a technique capable of using brake torque reception on the rotor turn-in and turn-out sides properly. Like the patent document 4 and 5, in a disk brake device which eliminates the outer bridge of the support, the torque of the outer side brake pad in braking can be received by a slide member.
Also, a brake pad for use in a disk brake device includes a brake pad (inner side brake pad) to be disposed on the inner side of a rotor and a brake pad (outer side brake pad) to be disposed on the rotor outer side. Especially, in some of floating-type disk brake device, the mode for holding an inner side brake pad and the mode for holding an outer side brake pad are different.
For example, in a disk brake device disclosed in the patent document 6, an inner side brake pad employs a holding mode using a support for supporting a caliper body. Meanwhile, an outer side brake pad employs a holding mode for hanging it on one end of a guide pin extended from the support.
Also, in the disk brake device of the patent document 3, the inner side brake pad is held by a rail-shaped guide provided on the bridge of the caliper body and a pipe-shaped guide mounted on the support. Meanwhile, the outer side brake pad is held by bolt fixing it to the pawl part of the caliper body.
Unlike the disk brake device of the patent document 3 and 6, the patent document 7 discloses a disk brake device in which holding modes for inner side and outer side brake pads are similar. The disk brake device of the patent document 7 adopts a support structured to straddle a rotor, and guide pins are projected toward the rotor arranged side respectively from the rotor inner and outer sides of the support to thereby hold the inner and outer side brake pads.